Field of the Invention
The aspect of the embodiments relates to a radiation detection apparatus, a radiation detection system, and a method for controlling a radiation detection apparatus.
Description of the Related Art
An apparatus includes a plurality of pixels, a scanning circuit, and a reading circuit. Each pixel includes a conversion element for converting radiations into an electric charge, and a switch element such as a thin-film transistor. As part of multi-functionalization, an automatic exposure control (AEC) function has been recently studied to build it into the radiation detection apparatus. With use of such function, the radiation detection apparatus can monitor a cumulative radiation irradiation amount, determine that the cumulative irradiation amount reaches an appropriate amount, and control a radiation source to end the irradiation. Operations such as the monitoring, determination, and control of the cumulative radiation irradiation amount (AEC operation) can be performed so that a region important for image diagnosis is rendered with a dynamic range. Examples of the diagnostically important region include a lung field in chest radiography and a bony part in limb bone imaging. For such purposes, a part or a plurality of regions in an imaging region of the radiation detection apparatus corresponding to such important regions is selected, as regions of interest and subject them to the monitoring and determination of the cumulative irradiation amount.
Japanese Patent Application Laid-Open No. 2013-135390 discusses a radiation image detection apparatus which uses a sensor substrate including pixels for obtaining a diagnostic image and a plurality of pixels for obtaining irradiation information. The radiation image detection apparatus can perform an appropriate AEC operation by dividing the detection pixels into monitoring target detection pixels and other detection pixels based on signal amounts of the respective pixels. Specifically, regions (non-irradiated field) not irradiated with the radiations and regions (through areas) of the radiation image detection apparatus on which the radiations are directly incident without passing through an object, are excluded from monitoring targets.
Japanese Patent Application Laid-Open No. 2013-135390 has the following three issues. A first issue is that the detection pixels located in other than the regions of interest are similarly read as the monitoring target detection pixels. Such a needless operation causes a lack of temporal resolution. A second issue is that a detection pixel which is suitable for an AEC determination is not determined until the irradiation of radiations is carried out. The determination may therefore be made based on an irradiation amount that includes information about regions other than the regions of interest. A third issue is a lack of spatial resolution due to the same cause as that of the second issue.